Celtics have been counting on Jonas Jerebko

Jonas Jerebko showed off his reach by challenging this shot by the Hawks’ Kent Bazemore during Game 4. Maddie Meyer/Getty Images

When Celtics coach Brad Stevens makes an adjustment or tries something new, he often refers to it as “throwing darts.” The suggestion is that he does not really know whether his hunch will work, or whether it is even a judicious move in the first place.

But the truth is that Stevens is usually not throwing darts. His decisions are most often rooted in something firm. Over the first two games of this playoff series against the Hawks — both Celtics losses — forward Jonas Jerebko was one of the few players who had been on the court while Boston outscored the Hawks.

Stevens also saw how the Hawks had bottled up Isaiah Thomas because of the lack of shooters around him, particularly with Avery Bradley sidelined, and he saw the need for a more versatile defender who is capable of switching on screens. So he threw a dart, or just made an important and well-informed choice.

Jerebko, who had not started during his 1½ seasons in Boston, was suddenly asked to help save this series. And so far, the switch has done wonders.

In each of the past two games as a starter, Jerebko has reached double figures in scoring and rebounding, matching his total from his first 111 games with the Celtics. His net rating of 10.1 — the number of points per 100 possessions the Celtics have outscored the opponent with Jerebko on the floor — is the highest of any Boston player who has appeared in each playoff game. The rating is twice as high as the next Celtic on the list, Marcus Smart, who was spectacular in Game 4.

“Playing more, feeling more involved, my teammates are giving me the ball in good situations,” Jerebko said when asked to explain his surge. “I’m just out there trying to play my butt off.”

Jerebko’s playing time has spiked from 15.1 minutes per game during the regular season to 26.3 in these playoffs. Most players would have a rise in production given such a substantial increase in playing time. But Jerebko has even raised his per-36-minute numbers, proving that he has been more efficient in these playoffs despite a greater workload.

After averaging 10.4 points, 8.8 rebounds, and 1.9 assists per 36 minutes during the regular season, he is averaging 12.3, 11, and 3.1 in the postseason. Also, his field goal percentage has increased from 41.3 to 45.5 and he has just one turnover during this series.

Aside from his own numbers, Jerebko has made a substantial ancillary impact, too.

“He spreads the floor for everybody,” Thomas said. “He allows us to drive and creates driving gaps. Then the way he can shoot the ball, he can pump-fake it or he can catch-and-shoot, and he’s doing a great job of taking advantage of his opportunities.

“Coach called his name and made an adjustment and we’ve been 2-0 since. He’s a big part of what we have here and he’s been playing well. And we need him to play like that.”

In Game 4 Sunday night, Jerebko’s offensive spark keyed the Celtics’ rally from a 16-point second-half deficit. With Boston trailing, 73-62, late in the third period, Jerebko scored 10 points over a stretch of 2 minutes, 2 seconds — a startling run usually crafted only by a dynamic offensive player like Thomas. He made two 3-pointers and a pair of challenging layups during the burst.

“We just wanted to cut that lead down,” Jerebko said. “We came into the fourth with confidence.”

For stretches of Game 4, Jerebko did struggle to defend Hawks forward Paul Millsap, who erupted for a career playoff-high 45 points. But Millsap scored on just about everyone besides Smart, and Stevens was not overly concerned. The Celtics are well aware of the value of having Jerebko on the floor.

“Jonas is a really good defender for us,” Stevens said. “He has been ever since he got here.

“He’s a big-time energy player. He’s going to have to just continue to study the guys he potentially will guard, and that’s a lot of guys, because we’re switching a lot of screens and so he’s guarding everybody from [Jeff] Teague on a possession to [Al] Horford at the end of the game.”